Curso académico 2011 – 2012

information procurement and of production control and also the problems which could arise for the above-mentioned group of individuals.

4.2.1 Tools and systems for the operative level ERP/PPS systems

A consequence of the fact that manual entries on time tickets and routing cards only become available in the ERP/PPS system with a time lag fre-quently of several days is that the following rule will necessarily apply: the closer to real time the information must be, the less the ERP/PPS system represents a genuine tool for the control of production. Information re-quired often at very short notice regarding order progress – and thus the delivery date as well – will, for example, not usually be available until the entire order has been completed. Due to the fact that the information is posted retroactively, information about material and inventory stocks (raw

4.2 The current situation in the manufacturing company 83 materials, semi-finished products, finished articles) will not be up to date and in many cases the employees will be laboring under false assumptions.

The necessary consequence is problems with the delivery dates and exces-sive or insufficient inventories. In addition, evaluations of orders and arti-cles (including statistical cost accounting) are often carried out solely with regard to commercial aspects and are only available with the lack of cer-tainty associated with a manual recording process subject to human error.

If the ERP/PPS system has to be used not only for its actual job of serv-ing as a rough plannserv-ing instrument but also as a tool for production con-trol, problems will arise in the detailed planning. Even today a large num-ber of ERP/PPS systems are still planning on the basis of an infinitely available capacity in production equipment. In practice there are however limitations in availability due to empty shifts and unpredictable circum-stances, such as machine faults, insufficient personnel with adequate quali-fications, unsatisfactory quality of raw materials, lack of corresponding tools, and so on. This lack of real-time status messages about these events, the lack of a suitable systematic facility to make this possible, and the lack of control mechanisms in the ERP/PPS system, all make the production control loop simply too sluggish. This in turn rules out a timely control response to counteract bottlenecks and situations of conflict. Production progress does not run as planned and delivery date statements made earlier bear no relation to reality.

Automation technology

The primary task of automation equipment is to regulate or control instal-lations, processes and machines on the technical level. During recent years systems of this kind have however developed more and more into an in-formation medium as well. As a rule it is not a problem for them to ac-quire, store and evaluate process values or other technical data such as, for example, machine faults. Where a shortfall can be detected when produc-tion processes are considered in their entirety is that they have no relaproduc-tion- relation-ship to planning or logistical data. Although the foreman or production scheduler can read off the technical state of the machine directly, the rela-tionship to the corresponding order whose manufacturing progress is af-fected by the fault has to be established manually in a roundabout fashion.

Nor is the machine control unit in most cases aware of other resources involved in production, such as tools, the material or even the personnel.

Quality systems

Logically enough, quality assurance systems focus on all events which have to do with the subject of quality. Although there is in fact a direct

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relationship between the production process and the quality produced, QA systems often operate autonomously and without being integrated into production. There is no system-based connection between the production order and the inspection order and the result of this is that there is no direct planning of inspection orders or inspection, measuring and test equipment.

In addition, quality data is analyzed without the necessary link to the un-derlying causes of quality problems on the shop floor (non-conformances caused by personnel error, poor material, tools, standstills and so on).

Usage recorders for logging machine data

The situation with these devices is similar to that with automation equip-ment: they have a one-sidedly technological “attitude” and the relationship to orders, to operating personnel or to the tools cannot be established, or only indirectly. Before it is possible to obtain electronic evaluations, the data have to be read out and then input manually into a separate system.

Another disadvantage is the recording process which is complex, requires intensive servicing and is also expensive (consumption of special forms, ink cartridges, and so on), not to mention the entire organization which has to put it place for supplying the consumables. Even the electronic pendants of the usage recorders (MDC systems, for example) will not improve the situation unless an automatic link is set up to the world of the orders.

Obsolete PDA systems

In the case of the PDA systems which were introduced a few years ago and which are subject to IT-related limits, in most cases users took a special approach. They were, for example, used as an information source for the data which are created at focal machines or operations, or when orders are reported as completed. In most cases they can only cope with evaluating single-stage production processes (for example, when the focal operation is injection molding) and are often only island solutions which lack inter-faces with the ERP/PPS system. In addition, here too a field of view cover-ing all resources is lackcover-ing, for example, covercover-ing tools, personnel or ma-terials.

4.2.2 Manual information procurement and other tools

To find a way out of the deficiencies described above, many companies are setting up facilities in addition to the systems mentioned with whose help urgently required information is obtained about the current event or plan-ning activities supported.

4.2 The current situation in the manufacturing company 85

Planning tables or pinboards

The advantage that the frequently used planning table or pinboard has over PC monitors is that it provides a clear large-area display of the planning scenario. Its function is, however, based on printouts of order documents from the ERP/PPS system and their complicated, manual deployment on the pinboard. This means a lot of effort required when new orders are added and especially when already inserted order cards have to be re-scheduled (urgent orders with a high priority, change in priorities, un-planned delays). Apart from visualization, the pinboard offers no kind of support for availability checks, for reviewing concatenated events or even in ascertaining what is the real capacity available, limited as it is by ma-chine faults or lack of personnel.

Progress chasers

As has been stated in the preceding chapters, without a PDA or MES sys-tem no current information about order progress will be available and for this reason no precise statements can be made “at the touch of a button”

about delivery dates and quantities. But since customers demand concrete information, in many companies the position of “progress chaser” has been created. His task is to gather all the necessary information about customer orders by walking the shop floor up and down. This involves a lot of per-sonnel time commitment and also means time delays caused, for example, by searching for parts.

Time tickets and routing cards

These are used for “transporting” the work on hand into the production areas and making information available about the orders or operations.

They do not, however, always reflect the current status since they are printed out from the ERP/PPS system and do not automatically keep up with quantities changed at short notice, with a new machine allocation or with changes in operation sheets and inspection and test plans. A lot of labor is involved in the workers filling out their time tickets and no plausi-bility check is made of the data. Further expense, time delays and often even errors arise since other employees then have to input the data by hand into the ERP/PPS system.

Clock cards

Even today clock cards are still used in many companies for documenting the employees’ clocking-in and clocking-out times and from these working

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out the hours they have worked as a basis for wage calculations. This in-volves a great deal of outlay on administration and materials. Here too additional labor capacities are required to calculate times and to input them into the wages and salaries system. In addition, an overview of which em-ployees are present and absent is only available locally at the time clock.

Work instructions, drawings and inspection and test plans Printed information is also a medium to which workers, line engineers, inspectors and foremen are accustomed. However, even these documents do not always show the current status since printing from the ERP/PPS, CAD or QA system does not take place in real time when production starts. A huge organizational and administrative overhead is involved in preparing, updating or distributing the documents.

4.2.3 Problems in bringing together the data

The systems and tools described above are in most cases island solutions and offer no way of exchanging data with other systems or if so only to a limited extent. The necessary all-round view is not however possible without an exchange of data or a comparison of data. Let us provide a few examples:

 To ensure gapless registration of productive times, the employees’ at-tendance times are compared with the productive times from PDA. This comparison is absolutely essential if performance-based or incentive payments are made.

 In short-term manpower planning the foreman on the one hand needs the information from time-off planning and staff work time logging (who is actually at work?) . On the other hand, the job load which has to be managed must of course be available as a result of detailed planning in order to make it possible to determine personnel requirements.

 Data must be brought together from different areas and systems when an explicit POP (proof of product) is required and when it must be docu-mented which employee made which part using which tool on which machine under what process conditions and using which batch of raw materials.